Toroidal magnetic cores having varying cross-sectional areas



. M. STIMLER TOROIDAL MAGNETIC CORES HAVING VARYING Feb. 7, 1967 CROS SSECTIONAL AREAS Original Filed Feb. 28, 1962 FHLH.

INVENTOR. MORTON STIMLER United States Patent 3 303,449 T OROIDALMAGNETFC CORES HAVING VARYING CROSS-SECTIONAL AREAS Morton Stimler,Hyattsville, Md, assignor to the United States of America as representedby the Secretary of the Navy Original application Feb. 28, 1962, Ser.No. 176,458. Divided and this application Feb. 28, 1964, Ser. No.

1 Claim. c1. 3ss 21s The invention described herein may be manufacturedand used by or for the Government of the United States of America forgovernmental purposes without the payment of any royalties thereon ortherefor.

This application is a division of my copending application, Ser. No.176,458, filed February 28, 1962 and now abandoned.

This invention relates to magnetic cores and more particularly tomagnetic cores adapted for progressive saturation.

With the use of progressive saturation techniques, the need has arisenfor magnetic core structures which provide increasing cross-sectionalareas along the lengths thereof. In this invention magnetic cores havingtapering non-uniform cross-sectional areas are provided which may beprogressively saturated. Toroidal cores having varying cross-sectionalareas are provided by making the cores of varying thickness or bylocating the hole within the toroid in an eccentric position.

An object of this invention is to provide a magnetic core having anon-uniform cross-sectional area.

A further object of this invention is to provide a toroidal magneticcore having a non-uniform cross-sectional area.

A still further object of this invention is to provide a toroidalpowdered iron core having a gradually changing cross-sectional areathroughout the length thereof.

Yet another object of this invention is to provide a toroidal laminatedmagnetic core having a non-uniform cross-sectional area.

Still another object is to provide a wound magnetic closed core having anon-uniform cross-sectional area.

Other objects and many attendant advantages of this invention will bereadily appreciated as the same becomes better understood by referenceto the following detailed description when considered in connection withthe accompanying drawing in which like reference numerals designate likeparts throughout the figures thereof and wherein:

FIG. 1 is a view of a circular powdered iron magnetic core;

FIG. 2 is a sectional view taken along the line 22 of the core of FIG.1;

FIG. 3 is a view of a powdered iron core having a tapering thickness;

FIG. 4 is a sectional view taken along line 44 of FIG. 3;

FIG. 5 is a laminated ferromagnetic core according to an alternativeform of the invention;

FIG. 6 is a sectional view taken through the line 6-6 of FIG. 5;

FIG. 7 is a view of a laminated ferromagnetic core having taperedlaminations;

FIG. 8 is a sectional view taken along line 88 of the core of FIG. 7;

FIG. 9 is a view of a tape wound core of progressively changingthickness;

FIG. 10 is a sectional view taken along the line 1010 of the core ofFIG. 9;

FIG. 11 is a developed layout of the tape used in making the core ofFIG. 9; and

FIG. 12 illustrates a tape wound core having laminations insertedbetween the layers of the magnetic tape.

3,303,449 Patented Feb. 7, I967 Referring now to FIGS. 1 and 2 of thedrawing, a powdered magnetic core 11 is shown having a hole within thecore 11 eccentrically located to provide a core having a cross-sectionalarea varying from a minimum at portion 13 to a maximum at portion 15with progressively increasing cross-sectional areas therebetween. Thethickness of core 11 is uniform as indicated in FIG. 2.

Referring now to FIGS. 3 and 4 of the drawing illustrating a powderedmagnetic core 17 having a hole concentrically disposed within core 17.In FIG. 4 it may be seen that core 17 has a tapered cross-sectionproviding for a maximum cross-sectional area of core material at 19 anda minimum cross-sectional area at 21 with varying intermediatecross-sectional areas therebetween.

Referring now to FIGS. 5 and 6 of the drawing, core 23 is made up oflaminations 25 each having a uniform thickness throughout. Unequalcross-sectional core areas are provided by the eccentric location of thehole therein.

Referring now to FIGS. 7 and 8 of the drawings, a core 27 is made up oflaminations 29 which have a tapering thickness assembled to provideunequal cross-sectional areas as illustrated.

Referring now to FIGS. 9, l0 and 11, core 31 is a wound core made fro-ma preformed tape 33 as shown in FIG. 11. With this type of core, thewider portions will be substantially aligned with each other to form alarge cross-sectional area of the core and the narrow portions will besubstantially aligned with each other to form a small or minimumcross-sectional area portion of the core.

Referring now to FIG. 12 of the drawing, a core 35 is made up ofconvolutions of tape 37 having constant width and thickness. Unequalcross-sectional areas are provided by strips 39, 41, 43, and 47 ofmagnetic material which are disposed between successive layers of tape37.

In operation a winding or windings, not shown, may be added to the coresillustrated to effect the desired progressive saturation thereof.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood, that within the scope of the appended claim, the inventionmay be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

A saturable core adapted for progressive magnetic saturation comprisinga generally toroidal shaped tape wound core formed from several layersof a ferrous tape material, a plurality of arcuate tapered laminationsof ferrous material aligned in a radial sector and disposed between thelayers of said tape material, whereby said core will havecross-sectional areas which progressively vary in magnitude from aminimum to a miximum to a minimum throughout one circumferentialrevolution of the core, said core having a single hole formed therein,said hole being circular and eccentrically disposed within the core.

References Cited by the Examiner UNITED STATES PATENTS 1,774,856 9/1930Van Deventer 336-233 X 1,875,590 9/1932 Green 336 X 2,799,822 7/1957Dewitz 336229 X 2,918,660 12/1959 Chen et al. 340-174 3,157,866 11/1964Lien 340174 FOREIGN PATENTS 1,100,710 4/ 1955 France.

LEWIS H. MYERS, Primary Examiner.

J. F. BURNS, L. E. ASKIN, R. K. SCHA'EFER, W. M.

ASBURY, C. TORRES, A ssistanl Examiners.

